Simulation Of Integrated Systems Of Evaporation Plants And Different Energy Conservation Techniques

Abstract

This paper describes the flowsheeting program EVAPSYS, developed for both design and evaluation calculations of any type of evaporation plants. The evaporation plant may be simulated either separately or integrated with an energy conservation unit such as a mechanical compressor, a steam ejector, or an absorption heat cycle. Different component modules are incorporated to provide the user with maximum flexibility in constructing any evaporation plant. These modules include an evaporator, heat exchanger, expansion vessel, mixer, splitter, mechanical compressor, and steam ejector. Other component modules are incorporated to enable the user to simulate single-stage absorption cycles. This arrangement allows the program to be executed in three different modes: evaporation plants, absorption heat cycles, and heat-pump-driven evaporation systems. Three subfunctions are incorporated for computing the overall heat transfer coefficients for falling-film evaporators, forced circulation heat exchangers and evaporators, and black liquor in vertical tube evaporators. The physical and thermodynamic properties of different liquors for evaporation applications and different working fluid pairs for absorption heat cycle applications are available in the database of the program. Three examples from the desalination, sugar, and pulp and paper industries are given to demonstrate the program capabilities in simulating complex flowsheets of evaporation systems.